The present invention relates to a continuous flow assay system for the measurement of chemical and biochemical analytes.
Analytical techniques using antigen/antibody or other biological affinity reactions have proved extremely useful in measuring minute quantities of substances. However, substantially all the techniques used to date only allow a static assay at a single point in time. While serial sampling is possible, this is often laborious or impractical. In these situations a continuous flow system would be a great utility.
U.S. Pat. No. 4,251,360 relates to an immunochemical antigen/antibody reaction for the detection and identification of either an antigen or an antibody. The method involves introducing successive mixtures of the sample with a set amount of one component of the reaction in tagged form and another component bound to a carrier into the reactant stream. Although the stream is continuous, the successive mixtures are separated by the insertion of an air segment into the liquid portion of the stream. The carrier is particulate.
U.S. Pat. No. 4,181,650 discloses a non-continuous competitive reaction for the detection and measurement of a ligand in a liquid sample. A tagged form of the ligand to be detected as well as an antibody having receptors is introduced into the fluid to be assayed. Any untagged ligand present in the fluid competes on an equal basis with the tagged ligand for the available binding or receptor sites on the antibody. The amount of untagged ligand is determined by measuring either the free tagged ligand or the tagged ligand/antibody complex. The tag is a chemiluminescent substance.
U.S. Pat. No. 4,067,959 also relates to a non-continuous competitive reaction for the quantitation of an antigen or antibody in a liquid sample. A first immunochemical, either antigen or antibody is immobilized on a small disk type solid support and the second immunochemical, specific to the first and tagged with a fluorescent compound, is bound to the first immunochemical. The immunochemical to be quantitated competes with the tagged second immunochemical for binding sites on the first immunochemical.
U.S. Pat. No. 4,205,952 relates to specific binding assays using labelled or tagged constituents. The particular tags are one or more metal atoms selected from various metalo-organic derivatives or metal coordination complexes. The following metals are disclosed: manganese, bismuth, silver, silicon, aluminum, zinc, gold, lead, cadmium, cobalt, iron, nickel, antimony, thallium, palladium, platinum and chromium.
U.S. Pat. No. 3,370,175 relates to a device to detect toxicants in gaseous or aerosol form. A culture of luminous organism is exposed to air which may contain a low concentration of toxicant. When a toxicant contacts the luminous culture, a rapid change in light output occurs which is detected by a photodetector. Although the culture can be exposed to air for a long period of time, this is a static reaction, not a continuous flow. Also, this is not a specific binding assay.
The following U.S. patents relate to the general subject of non-continuous specific binding assays: U.S. Pat. Nos. 4,092,408; 4,222,743; 4,254,084; 4,493,793; 4,510,251 and 4,526,871.
U.S. Pat. Nos. 4,113,434 and 4,388,411 relate to devices and methods for sampling gases from a fluid flow. U.S. Pat. No. 4,113,434 is a continuous sampling method.